1. Field of the Invention
This invention is in the field of seat belt systems.
2. Description of the Prior Art
Seat belt systems are available combining a lap belt and upper torso belt. Typically, a single belt having its opposite ends mounted to a pair of retractors has a seat belt tongue mounted to the belt intermediate the belt ends. The tongue may then be swung across the person and engaged with a buckle affixed to the seat thereby positioning one portion of the belt across the lap and another portion of the belt across the upper torso. Instead of mounting both ends of the belt to a pair of retractors, some systems have only one end of the belt mounted to a retractor whereas the opposite end of the belt is affixed to the vehicle.
Rough riding equipment, such as trucks, provide special problems in relationship to seat belt systems. Slack inducing mechanisms are typically required to isolate the driver from belt pressure created by retractor lock up. Certain slack inducing mechanisms do not automatically provide for constant belt tensioning and constant belt pressure applied to the driver. The system disclosed herein reduces or eliminates the discomfort from belt pressure and cinching without the use of slack inducing mechanisms.
It has been the prior approach to increase the strength of the vehicle floor and seat in order to reduce the motion between the seat and vehicle which occurs during a crash. Such modifications are costly and require more expensive seats. Disclosed herein is a tether system which minimizes such relative motion while allowing for use of relatively inexpensive seats and elimination of any additional strengthening or rigidizing of the vehicle floor.